Figure 9. Overview of the model used in this study.

The stimulus is external and the subsequent processing is done in two stages. The first stage is small-field motion detection and corresponds to the signal transformation in the lamina and medulla of fly. The second stage corresponds to the wide-field motion integration. In this model, small-field motion detection is performed by Reichardt detectors. The outputs of the small-field motion detectors are projected onto the integrator cell in a biologically accurate way as illustrated. Each small-field motion detector is connected to the integrator cell through an excitatory and inhibitory ribbon synapse that convey graded potentials. Illustrated is a random cell with its connections. The number of detectors shown in the figure is reduced from the actual 20 to 4 for the sake of clarity.